Intersubject EEG coherence: is consciousness a field?

EEG coherence was measured between pairs of three different subjects during a one-hour period practice of the Transcendental Meditation (TM) program. Coherence between subjects was evaluated for two sequential fifteen minute periods. On six experimental days, these periods preceded and then coincided with a fifteen minute period during which 2500 students participated in the TM-Sidhi program at a course over 1000 miles away. After the course had ended coherence was evaluated on six control days. It was found that intersubject coherence was generally low, between 0.35 and 0.4, with coherence in the alpha (8-12 Hz) and beta (16-20 Hz) frequencies significantly higher than at other frequencies. On the experimental days, intersubject EEG coherence increased during the experimental period relative to the fifteen minute baseline period immediately preceding the experimental period. Coherence increased significantly from baseline to experimental periods on experimental days compared with control days (p = 0.02). This effect was particularly evident in the alpha and beta frequencies. The results reinforce previous sociological studies showing decreased social disorder in the vicinity of TM and TM-Sidhi participants and are discussed in terms of a field theoretic view of consciousness.